Johnson Controls has installed two YORK chillers at the South African offices of a leading multinational tech company. The combination of a water-cooled and heat-pump chiller will meet the needs of the company’s 600+ people in their almost 10,000m2 facility in Johannesburg, and provide considerable energy savings, especially with Johnson Controls’ Central Plant Optimisation (CPO 10) app in place.

Notes Neil Cameron, Area General Manager of Johnson Controls Building Efficiency – Africa: “This project is a key example of how new technology can be combined using advanced HVAC management tools to increase performance, maximise investments in HVAC equipment, and lower energy costs.” After assessing client requirements, Johnson Controls recommended that the technology company replaced its 13-year-old air-cooled chiller that had reached end-of-life with a 700kW water-cooled YMC2 chiller and 300kW YLPA heat pump chiller.

The main YMC2 chiller will take 65% of the load of the facility, while the heat pump will be employed when additional air-cooled capacity is required, as well as to heat air intakes in winter. What makes intelligent automated switch-over possible is the addition of the Johnson Controls Central Plant Optimisation (CPO 10) application coupled with the customer’s existing building management system.

“The CPO 10 takes into account external conditions, what ancillary equipment is available, and the performance of the machines at full and part load,” explains Cameron. “Based on its analysis of most efficient performance and associated cost, it will select the most efficient combination – automating switch-over or the addition of capacity, or other configured actions within the framework of the energy strategy set by the customer.”

These benefits are in addition to the design advantages the YMC2 chiller brings: friction-free operation with magnetic bearings that extend the life of the chiller to approximately 20 years. With the heat pump chiller also in play, the heating elements previously used to heat chiller water in winter can be removed and replaced with hot water coils driven by the heat pump. This will result in significant energy savings.

“Compounded over 20 years, the savings in running costs using the water-cooled YMC2 chiller are considerable,” Cameron notes. “The client had a choice – replace the legacy chiller with another of the same capacity, or make a slightly larger investment in a combination solution. While this required a larger initial investment, the time to return on investment is just 3.5 years. Savings in the running cost of the combination solution over 20 years -- R21 million vs R30 million for a smaller capacity air-cooled solution – made this solution the smart choice.”

The chillers were commissioned in December 2014 and have performed to expectation.